Transmission electron microscopy of indium gallium nitride nanorods grown by molecular beam epitaxy

This paper demonstrates the growth of InGaN nanorods and lateral growth over nanorod arrays using molecular beam epitaxy. It is shown that nitrogen rich growth conditions result in a nanorod array and that, by changing to metal rich conditions, lateral growth may be enhanced to coalesce the nanorods into a continuous overgrown film. Energy dispersive X-ray spectroscopy has been used to demonstrate that the nanorods display a core-shell structure with In-rich cores and In-poor edges. Transmission Electron Microscopy has shown that the nanorods are free of dislocations. However, when lateral growth occurs basal plane stacking faults are generated. It is shown that this stacking fault generation leads to a change in structure from hexagonal to cubic. When coalescence has occurred large angle grain boundaries are present.